1. Field of the Invention
The present invention relates to a core sampling apparatus that samples a core while maintaining an internal pressure of the apparatus and a container transfer apparatus that transfers a container in the core sampling apparatus to a predetermined apparatus.
2. Related Background Art
In scientific drilling, etc., although many researchers and engineers have been making developments for the purpose of obtaining a stratum column-shaped sample (a core) with a pressure in the stratum maintained for many years, they are still far from completion. Recently, in oil field drilling, there has been a special coring system called a “pressure temperature core sampler (PTCS)”, which has been developed mainly for the purpose of obtaining a core of methane hydrate, in particular under pressurized conditions (that is, in a hydrate condition) (see Patent Literature 1 (U.S. Pat. No. 6,216,804)). This PTCS is provided with a thermal electronic cooling apparatus and has a characteristic that it can perform recovery while preventing the vaporization of methane hydrate since it performs to maintain a pressure and cool.
If the core is drilled and recovered using the PTCS, the recovery time is short, and thus the temperature rise during the recovery does not cause much of a problem. In consideration of this, there is also an NC-PTCS, which aims to improve the pressure maintainability by removing a cooler, and further solving the problem that a rotation angle of a ball valve rotated by a link is inaccurate, and improving an ability to stop at a designated position (see Non-Patent Literature 1 (“Pressure Temperature Core Sampler (PTCS)—Core Sampling Technology for Maintaining Pressure and Temperature” by Kawasaki, Umezu, and Yasuda, Journal of The Japanese Association for Petroleum Technology Vol. 71, No. 1, The Japanese Association for Petroleum Technology, January 2006)).
However, even in this NC-PTCS, since an apparatus for sampling a column-shaped sample (a core sampling apparatus) has a large outer diameter, it is also difficult to drilled by using a conventional drill pipe. Further, the NC-PTCS includes no consideration of moving the core to an analyzing device while maintaining real pressure conditions below the seabed. In order to solve these shortcomings and recover the core while maintaining a real pressure environment below the seabed, a core sampling apparatus which recovers the core while maintaining an internal pressure of the core sampling apparatus has been developed (for example, see Non-Patent Literature 2 (“Development of Hybrid PCS (pressure conserving core),” by Mizuguchi, Kobayashi, and Inada, Collection of Summaries of special lectures, symposiums and private lectures at the spring lecture meeting of The Japanese Association for Petroleum Technology, 2012, The Japanese Association for Petroleum Technology, June 2012). This core sampling apparatus (a core barrel) includes a running and retrieving unit (a detaching unit) located in an upper portion thereof, a pressure control part located in a middle part thereof, and a core sampling unit (an autoclave) which is located in a lower portion thereof and provided with a pressure conserving function.
In order to obtain a core, for the purpose of inserting the core into a core liner (a container for recovering the core) located in the autoclave by drilling, the core sampling apparatus should have a structure in which internally circulating mud water is released from the upper portion thereof. In order to maintain a pressure in the core barrel, it is possible to maintain pressure tightness in the autoclave by blocking an upper hole formed on the upper portion of the autoclave positioned in the lower portion of the core barrel and closing an openable and closable ball valve located in the lower portion of the autoclave. This ball valve has a structure in which a pressure can be maintained by sealing only a portion that penetrates the ball valve by disposing a ball valve seal in the upper portion of the ball valve; thus the ball valve has a structure whereby it is possible to form the autoclave itself with a small outer diameter and obtain a core having an outer diameter sufficient for analysis.
In the ball valve, when a spring retainer (a sleeve) located in the upper portion of the ball valve is removed, the ball valve is moved downward by pushing the ball valve with the spring, whereby rotation of the ball valve is controlled, and the ball valve can be closed as it is rotated just like rolling. After that, by using an accumulator disposed in the pressure control part, pressurized water adjusted to apply a pressure higher than the pressure of the stratum is injected. Therefore, it becomes possible to maintain the internal pressure of the autoclave higher than the pressure at the seabed, and the core is recovered to the surface of the earth with an improved ability to maintain pressure. This pressure adjusting function can be used to adjust the pressure maintenance by pressurizing to a set pressure automatically even when the pressure in the autoclave leaks while the core is being recovered to the surface of the earth.